# unexplained

/ˌənɪksˈpɫeɪnd/ (US) · /ˌʌnɛksplˈeɪnd/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/unexplained
Updated: 2026-05-07

## Definition

describing something that has no clear reason or cause. You use this when nobody can find a logical way to explain what happened.

For teachers: lacking a known cause, reason, or explanation. Often used to describe mysterious phenomena or sudden changes in data.

## Examples

- The police are investigating his unexplained disappearance.
- The scientists were baffled by the unexplained drop in temperature during the experiment.
- While most of the symptoms were typical for the virus, the patient exhibited several unexplained neurological signs that suggested a more complex underlying condition.

## Pitfalls

- Not "The reason was unexplained of." but "The reason was unexplained." — Learners sometimes try to add a preposition like 'of' or 'about' after the adjective, but it is typically used alone.

## Usage notes

- Typically used attributively before a noun; when used predicatively, it often follows 'remain' or 'be'.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.